Cyclosporin has improved survival rates in patients undergoing heart transplants because it reduces the incidence of acute rejection episodes, but acute rejection still remains an important clincal problem. One of the most important predisposing factors for acute rejection is a sub-therapeutic plasma concentration of cyclosporine. Wide variability has been observed in the absorption, distribution, liver metabolism and therapeutic efficacy of cyclosporin, due largely to poor absorption of the drug after oral administration. Absorption of the oil-based formulation of cyclosporin requires adequate bile flow to the gastrointestinal tract. SANG-35 is a reformulation of cyclosporine that facilitates gastrointestinal absorption, producing controllable and consistent cyclosporine levels. SANG-35 has been tested in normal volunteers and in renal transplant patients but not in heart transplant patients.